Not building boost at all? Possibly the throttle body

[Alexvance]

I went to home depot yesterday and made myself a little boost leak tester, when I got come and stuck it on the car at the turbo inlet I was surprised to find that the only audible leak at 20 psi was coming from the throttle body spring thing at the back.

So I've been looking at the throttle body leak threads, and I'm pretty sure that's my problem and I'm going to replace the seals.

But I want to know, can that cause me to be losing nearly all of my boost? I mean I don't feel the turbo at all when I drive now. Could the throttle body be leaking that badly? I hear a whine that sounds a little like the turbo spool, but at a higher pitch (So I think that's the leak from the TB). Could there be something else wrong?

I'll be investing in a boost gauge very soon (i.e ordering one as we speak), but until then any help at all would be very appreciated.


P.S
This is the gauge / pod combo I'm going to buy:

95-99 Mitsubishi Eclipse Custom Gauge Package

What's the "oil filter adapter" option, and will I need one? (Planning on getting boost, egt and oil press.)

 

[Dsmj89]

I believe the oil filter adaption option is an option in which it will bring a special bung/connector in which you can mount to the oil filter housing to get your oil pressure reading from there.
If you are getting a leak through the TB area, i would start off by replacing both gaskets in front and after the TB and then take it for a run and see how it does.
However, just cause you have a minor leak at your TB does not mean you should be losing all your boost.
Make sure also your clamps are all nice and tight and your mas is plugged in.

 

[Alexvance]

I believe the oil filter adaption option is an option in which it will bring a special bung/connector in which you can mount to the oil filter housing to get your oil pressure reading from there.
If you are getting a leak through the TB area, i would start off by replacing both gaskets in front and after the TB and then take it for a run and see how it does.
However, just cause you have a minor leak at your TB does not mean you should be losing all your boost.
Make sure also your clamps are all nice and tight and your mas is plugged in.

Thanks for clarifying, I also just called their customer service and what you said was correct.


The clamps are all good as far as I know, I replaced the t clamp next to the turbo with a new worm clamp because I think I can get that a little tighter. But other than that everything seems good, mas is indeed plugged in.

I don't understand why I'm not getting any boost. (Gauge pod ordered, so that boost gauge will probably help out a little.)

 

[Dsmj89]

Have you taken off your intake pipe and make sure ther's nothing in the turbo's mouth ?
Also, make sure your wastegate isn't stuck open.

 

[Alexvance]

Have you taken off your intake pipe and make sure ther's nothing in the turbo's mouth ?
Also, make sure your wastegate isn't stuck open.

I've had the intake off several times and there wasn't much in there... just some oil from what I could see (I'll take it off after work tomorrow again and look inside it) Can't do it now because it's too hot.

As for the wastegate, how do I check if that's stuck open?

edit: Tried moving the arm on the wastegate a little, didn't seem to budge.

 

[Dsmj89]

Spray some wd-40 on the arm and lever and let it sit for 5 minutes, then give it a try.
Also, why don't you turn on the car without the intake system on and see if the turbo wheel spins ?
Can't think of anything else atm, get the thottle body leak fixed and let me know how it goes after that.

 

[Alexvance]

Spray some wd-40 on the arm and lever and let it sit for 5 minutes, then give it a try.
Also, why don't you turn on the car without the intake system on and see if the turbo wheel spins ?
Can't think of anything else atm, get the thottle body leak fixed and let me know how it goes after that.

I'll do that thing w/o the intake on tomorrow (or today as it would be now) And I'll maybe take the throttle body to a mechanic to have them replace the seals, as I don't feel confident messing with something so critical.

Thanks for your help, I'll get back to you once I've done the intake thing.

 

[Alexvance]

Okay so here's an update:

I took of the intake again and looked at the turbo.

The thing is pristine. No shaft play at all, spun well and the fins looked good from what I could see.

You must be logged in to view this image or video.

I stuck my diy boost leak tester on the intake inlet of the turbo and put around 20psi in the system. The loudest leak was coming from the throttle body, and after a bit of spraying I found out it was coming from this spring thing:

You must be logged in to view this image or video.

(That was me spraying it as I took the pic, not the liquid being squirted off or anything)

And this screw:

You must be logged in to view this image or video.

The screw is horribly rusted, and I don't know what to replace it with. I tried tightening it, but that didn't work. I tried to unscrew it out, but once it got to the end of the thread, the head wasn't poking out enough to grab it.

This tube thing was putting air out too:

You must be logged in to view this image or video.

But I think that's because I don't know how to put the piston at TDC.

And finally the stock BOV was (of corse) leaking.

You must be logged in to view this image or video.

The diaphragm doesn't seem to be all the way at the bottom, even at idle. This shouldn't be the reason for me not having any boost at all though. (and I have a new one in the mail).

Any more help guys? I'm probably going to take the throttle body to a mechanic today to have it re-built or at least re-sealed.

 

[snowborder714]

You need new shaft seals (they are underneath the springs on the back) and a new BISS o-ring and screw (the Philips head screw on the front that won't come out).

 

[Jdog]

That screw you have been backing out is the BISS like snowboarder714 said and that is responsible for adjusting the idle of the car when the FIAV isnt messing with it at all. Do as he says

 

[95redturboawd]

I really don't see the throttle body leak causing you to not boost at all. The leaking bov is much more likely the problem.

 

[Alexvance]

I really don't see the throttle body leak causing you to not boost at all. The leaking bov is much more likely the problem.

I didn't think so either. I'm taking it to a mechanic again on Friday (they didn't find anything today, said they needed more time) to get it smoke checked. Then we'll see where all my boost is going.


Please don't be a hole in the intercooler

 

[Kash]

+1 for the throttle shaft seals, im having the same problem almost to a t. Except i start losing air around the spring at 12 lbs. Also as of now that is the only place im losing air.

 

[Alexvance]

+1 for the throttle shaft seals, im having the same problem almost to a t. Except i start losing air around the spring at 12 lbs. Also as of now that is the only place im losing air.

And that's causing you to lose almost all your boost? I'm getting nothing.

 

[95redturboawd]

It's highly unlikely, mine were leaking too as well as at the BISS screw but they're such small leaks that there's no way you wouldn't build ANY boost. When you say it doesn't feel like it's boosting, how do you know this? Do you have an aftermarket boost gauge?

 

[Alexvance]

It's highly unlikely, mine were leaking too as well as at the BISS screw but they're such small leaks that there's no way you wouldn't build ANY boost. When you say it doesn't feel like it's boosting, how do you know this? Do you have an aftermarket boost gauge?

No, it's coming in the mail. The car used to boost just fine, I know the difference. I'm not getting any additional power.

 

[95redturboawd]

Maybe if you did another boost leak test and plugged the hose in that fourth picture you could get more accurate results.

 

[Alexvance]

Maybe if you did another boost leak test and plugged the hose in that fourth picture you could get more accurate results.

Thought of that Plugged it up and waited to see if any new leaks popped up, but couldn't hear any.

 

[rEclipserGST]

Thought of that Plugged it up and waited to see if any new leaks popped up, but couldn't hear any.

How fast can you get the car going (mph wise) with "no boost"?

 

[habitatguy187]

Good idea to check your pcv valve also, if it's bad then it will leak boost from the intake manifold, through the pcv valve on the valve cover, through the valve cover, and out the crank case breather (that little hose you took a pic of) To test it take the pcv valve out (link below) and try to blow through it, if you can blow air from the intake manifold side to the valve cover side, then the pcv valve is bad.

TB shaft seals are quite easy also, just take your time, here's some helpful links.

BISS

PCV Valve

Throttle Body O-Ring

If the TB leaks at 20psi though, it won't leak while driving until you hit 20psi. Let us know what happens when you get the new bov on.

 

[Kash]

see mine i hit boost, but wont go any higher then 10-12 lbs, even though the mbc is set for approx 15 lbs.

 

[95redturboawd]

Your mbc is probably set up incorrectly causing your car to run off the wastegate pressure.

 

[Kash]

No, its not theres only two possible ways for it to be hooked up. I know for a fact its hooked up correctly.

 

[habitatguy187]

Your mbc is probably set up incorrectly causing your car to run off the wastegate pressure.

Wastegate pressure is much more than 0-2psi. On a 1g it's around 9psi.

 

[Alexvance]

Good idea to check your pcv valve also, if it's bad then it will leak boost from the intake manifold, through the pcv valve on the valve cover, through the valve cover, and out the crank case breather (that little hose you took a pic of) To test it take the pcv valve out (link below) and try to blow through it, if you can blow air from the intake manifold side to the valve cover side, then the pcv valve is bad.

TB shaft seals are quite easy also, just take your time, here's some helpful links.

BISS

PCV Valve

Throttle Body O-Ring

If the TB leaks at 20psi though, it won't leak while driving until you hit 20psi. Let us know what happens when you get the new bov on.

I'm taking it to get smoke tested tomorrow, I'll post the results and maybe I can help some other people here having the same problem (and bite the expensive labor hours bullet)

Once I find out where the major problem is and fix that, I'll buy a new BISS from the site linked a few posts back along with an o ring for it, then if I'm feeling brave I might take a look at the TB... more than likely I wont though After that I'll blow on the thing you told me to (PVC) and replace that if necessary.

I'm also going to order the upper intercooler S and L pipe from Dejon, the L pipe pre-flanged for a greddy type S. Then I'll mount my non leaky new bov .

And finally I'll put that boost gauge in when it comes, hopefully I can do that by myself

over $900 blown in one week so far payday tomorrow though!